Table of Contents | PREVIOUS PAGE | NEXT PAGE

Typical spectral measurements of normal and tumorous esophagus are shown below. The spectra are a measurement on tissue normalized by a measurement of the 2% lipid solution standard.

The spectral data are the symbols. The lines are the curve fit. The values cited in each figure are:

• a and b indicate the reduced scattering coefficient = a(nm)^-b.
• fv indicates the volume fraction of blood at 45% hematocrit in the tissue.
• S indicates the average oxygen saturation of the blood.
• const is a wavelength-independent factor that accounts for optical fiber-tissue contact variation
• W indicates the water content of the tissue

The black line called "bloodless" shows the expected measurement if all the blood was removed from the tissue.

Figure 1: (LEFT) Normal tissue. Blood content is 0.74%. (RIGHT) Tumor. Blood content is 2.7%. (b values are listed as -b.)

Figure 2: (LEFT) Same normal tissue as above, but showing curves for 100% oxy- and 100% deoxy-blood. (RIGHT) A second tumor site with higher blood content (14%) illustrating how near-infrared spectral fitting is appropriate when high blood content is encountered. (b values are listed as -b.)

Table of Contents | PREVIOUS PAGE | NEXT PAGE